NATURE'S LAWS 317 



the seedling can feed itself. Many insects which 

 do not see their little ones nevertheless work for 

 them in a most beautiful manner. If the larvae 

 feed on some particular plant the mother searches 

 for it, often wandering for miles. Then she 

 appears to study one situation after another before 

 deciding to lay her eggs. The solitary wasp 

 builds a mud cell, or excavates a burrow, humming 

 with pleasure at her work. When this is ready, 

 off she goes to bring some fat caterpillar or a 

 grasshopper bigger than herself, dragging it along 

 by a series of flying leaps. The wonderful manner 

 in which she paralyses without killing this pro- 

 vision supply is one of the most interesting things 

 to a close observer. The food on which she lays 

 her eggs is still alive when the larvae come out 

 of their shells ; neither dry nor putrid. When 

 building she resents interference, as we found out 

 on one occasion when going too close to the 

 place where one of the mud-daubers was working. 

 The sting was more paralysing than painful, 

 extending from the ringer to the shoulder and 

 lasting for three days. During this time every 

 movement of the hand or arm was painful. 



Parental care is, however, most conspicuous in 

 birds, marsupials, and mammals. The callow 

 and helpless little ones require more care because 



